Okay kiddo, direct flight means that you get on an airplane in one city and you don't have to get off until you get to your destination. It's like a long ride on a bus or car, but you're in the sky!
So let's say you live in New York and you want to visit your grandma in Florida. You book a direct flight from New York to Florida on an airplane. The airplane takes off from the airport in New York, flies straight to Florida, and lands at the airport there.
The important thing to remember about a direct flight is that you don't have to switch planes or make any stops. You just stay on the same plane until you reach your destination. That's why it's called a direct flight, because it's a straight path from one place to another without any interruptions.
Direct flights can be really convenient because you don't have to worry about missing your connection or dealing with delays. It's just one smooth flight from point A to point B. And that's direct flight explained like you're 5!